1. Field of the Invention
This invention relates to an exit device--that is, a door latch operated by a horizontal panic bar or press plate--having concealed vertical latch operator rods which are adjustable in length. More particularly this invention relates to an exit device having concealed rods which are adjustable in length from outside the door structure.
2. Description of Related Art Including Information Disclosed Under .sctn.1.97 to 1.99
In the prior art in has been fairly common to provide an exit device with vertical rods which are concealed in the hollow shutting stile of the door. These rods, which are vertical, extend both up and down from the exit device to operate latch means which cooperate with respective receivers in the door lintel and threshold.
Because the latch mechanisms are assembled after the door is installed, the vertical rods often require lengthwise adjustment so that the latching will operate properly. This is true when the latches are initially installed in the door and also when the frame "works" (that is, changes dimension and shape slightly) as the building settles.
In the past, with the panic devices having vertical rods which are surface mounted on the inside face of the door, vertical adjustment of the rods has been easy: it has been merely necessary to wrench around the threaded end of the rod which fits into a threaded fitting in the latch-operating mechanism, to thereby change the length of the rod. By "length of the rod", of course, what is meant is the distance from the latch-operating mechanism to the remote end of the rod in a given position of the operation of the mechanism.
With the advent of conceal rods, the adjustment of the rods has been made somewhat more complicated because the rods are inaccessible from outside the door. Often the door would have to be taken off its hinges and the end of the rod turned to change length.
An early attempt to solve this problem with concealed rods is disclosed in U.S. Pat. No. 1,721,489 issued Jul. 16, 1929 to Prinzler. In this patent each rod fits into a boss in the latch mechanism and is held therein by a set screw which, when the latch face plate is removed, may be loosened so that the length of the rod may be adjusted. The set screw may then be reset.
Another attempt is disclosed in U.S. Pat. No. 2,887,336 which issued May 19, 1959 to Meyer. In this arrangement the rod terminates in a plate which has a sawtooth surface to mate with a sawtooth surface on the latch mechanism operator. A screw is provided to hold the sawtooth surface in engagement, the screw being loosened to readjust the sawtooth surfaces if necessary, and then tightened.
The U.S. Pat. No. 3,940,886 which issued Mar. 2, 1976 to Ellingson, Jr. has the rods attached to separate operating members which are connected by a threaded member, the threaded member being engageable by the panic bar.
The Kim U.S. Pat. No. 4,601, 499 which issued Jul. 22, 1986 attaches the rods to horizontal limbs held on the latch housing by threaded elements which are mounted in special boxes slideable against the housing as the push plate is depressed.
Finally, U.S. Pat. No. 4,881,765 to Heid which issued Nov. 21, 1989, permits adjustment of the vertical rods by relative movement of two inclined interfitting blocks which may be move relatively by threaded means on the end of the door.
Other patents generally of interests of this subject, but not showing concealed rods, are U.S. Pat. Nos. 3,819,213 issued Jun. 25, 1974 to Vanderburgh, 4,598,939 which issued Jul. 8, 1986 to Krupicka et al and 4,796,931 which issued Jan. 10, 1989 to Heid. The latter three patents are assigned to my assignee.